Wafer backside plate for use in a spin, rinse, and dry module and methods for making and implementing the same

ABSTRACT

A method for spinning a wafer to enable rinsing and drying is provided. The method includes engaging the wafer at a wafer processing plane and spinning the wafer. The method further includes moving a wafer backside plate from a first position to a second position as spinning of the wafer proceeds to an optimum spinning speed. The second position defines a reduced gap between an under surface of the wafer and a top surface of the wafer backside plate. The method also includes repositioning the wafer backside plate from the second position to the first position as the spinning reduces in speed. The first position defines an enlarged gap to enable loading and unloading of the wafer from the engaged position.

CROSS-REFERENCE TO RELATED APPLICATION

This Application is a divisional of application Ser. No. 09/747,660,filed on Dec. 22, 2000, entitled “WAFER BACKSIDE PLATE FOR USE IN ASPIN, RINSE, AND DRY MODULE AND METHODS FOR MAKING AND IMPLEMENTING THESAME” from which priority under 35 U.S.C. § 120 is claimed. Thedisclosure of this Application is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to semiconductor wafer cleaningand, more particularly, a chuck assembly and a wafer backside plate tobe used in semiconductor substrate spin, rinse, and dry (SRD) modules.

2. Description of the Related Art

Particulate contaminants generally consist of tiny bits of distinctlyOne commonly used wafer preparation operation used at various stages ofsubstrate preparation is a spin, rinse, and dry (SRD) module.Conventionally, the wafer is spin rinsed by spraying deionized wateronto the top and backside of the wafer, as the wafer is spun around athigh speed. The spin rinse operations are typically performed in a bowlrigidly mounted on an SRD housing designed to receive a spindle coupledto a motor. As the motor rotates, so do the spindle, a chuck mounted onthe spindle, and the wafer. Customarily, the chuck supports the edges ofthe wafer by utilizing four spindle fingers coupled to the chuck. Thespindle fingers are designed to move upwardly out of the bowl such thatthey extends outside the bowl housing. Thus, customarily, the wafer isdelivered to the spindle fingers while they are extended out side of thebowl at a level above wafer processing plane. Once the wafer isdelivered to the spindle fingers, the chuck having the spindle fingersand wafer attached thereto moves back down and into the bowl so as toplace the wafer at the level of wafer processing plane.

Typically, fluid (e.g., DI water) is supplied to a spigot and thus ontothe surface of the wafer, as the wafer is spun at high revolutions perminute (RPMs). When the surface of the wafer is sprayed with fluid, thesupplying of fluid is stopped by turning off the spigot, and the waferis dried as the wafer continues to spin at high RPMs. Once the wafer isdried, the processed wafer is unloaded by moving the chuck and spindlefingers holding the wafer upwardly out of the bowl until the wafer isextended above the wafer process plane for a second time. At this time,an end effector can reach in and remove the wafer from the SRD module.

Numerous shortcomings can be associated with chuck assemblies ofconventional SRD modules. Primarily, the typical SRD module requires acomplex chuck design. For instance, the chuck is commonly required tomove up and down. The chuck moves up to receive the wafer, moves down toprocess the wafer and then up again to remove the wafer from the SRDbowl. In view of this continual movement activity, it is imperative thatthe chuck remains properly calibrated so that it comes to rest at theexact process level. In situations where the chuck is not properlyaligned, failure to properly receive and deliver the wafer mandates therealignment of the chuck. The process of realigning of the chuck is verytime consuming and labor intensive, and it requires that the SRD modulebe taken off-line for an extended period of time, thus reducingthroughput.

Another shortcoming of conventional chucks is the unnecessary movementsrequired in loading and unloading of the wafer to and from the fixedspindle fingers. Predominantly, in conventional SRD modules, the loadingof the wafer onto the fixed spindle fingers involves four stages. Thatis, to receive a wafer, initially, the chuck is moved upwardly and outof the bowl, such that the chuck is positioned above the wafer processplane. As a result of having fixed spindle fingers, to deliver theunprocessed wafer to the edges of the spindle fingers, at the outset,the end effector having the wafer is moved horizontally over the bowl ata level that is above the horizontal plane of the spindle fingers (whichare already in the up position). Thereafter, the end effector must movedownwardly (while over the bowl) until the wafer reaches the level ofthe spindle fingers. At this point, the spindle fingers can engage thewafer. Once the spindle fingers have engaged the wafer, the end effectorrelinquishes the wafer and thus physically delivering the unprocessedwafer to the spindle fingers. Finally, to pull out, the end effector isrequired to move slightly down and away from the wafer under surfacebefore moving horizontally away from over the bowl. Each of the up anddown movements of the end effector are performed using the “Z” speed ofthe end effector, which in fact is a significantly low speed. As such,the performing of a spin, rinse, and dry operation on each waferrequires a significant amount of time simply to load and unload thewafer, thus increasing the SRD cycle per wafer. As can be appreciated,this reduces the overall throughput of the SRD module.

Yet another shortcoming associated with conventional chucks of SRDmodules is the creation of air turbulence above the wafer surface. Thatis, as the chuck and thus the wafer spin in the bowl, the spinningaction of the chuck and the wafer transfer energy to air flowing overthe topside of the wafer. This transferred energy causes the airflowabove the topside of the wafer to become turbulent and thus createsrecirculating air (i.e., eddies). The amount of energy transferred tothe air flowing to the topside of the wafer depends on the diameter andthe rotational speed of the wafer. In general, the greater the amount ofenergy transferred to the air, the higher the eddies extend above thetopside and the farther the eddies extend below the backside of thewafer. The presence of eddies below the wafer is undesirable becauseparticles or DI water droplets removed from the wafer can circulate inthe eddies and can be re-deposited on the backside of the wafer, therebycausing wafer recontamination.

Further challenges faced in the use of conventional chucks are thelimitations associated with the chuck geometry. Mainly, the relativelylarge size and associated weight of conventional flat chucks necessitatethe use of significantly higher amounts of energy to operate the SRDmodule. Additionally, the large size of the chuck further requires theuse of larger shafts as well as spindles. Collectively, theselimitations mandate the use of a larger and more powerful motor, thusincreasing the cost of the SRD modules as well as the associatedoperating cost.

Yet another challenge faced in the use of chucks in SRD modules ishaving chemically incompatible components present within the modules. Ina typical SRD module, most components are constructed from severaldifferent materials. For instance, the chuck is usually constructed fromAluminum, while the bowl is made out of Polyurethane, and the spigot ismade out of stainless steal. As a result, particles or contaminants fromchemically incompatible components may enter into chemical reaction withthe fluids introduced into the SRD module, thus further recontaminatingthe SRD module. This recontamination can further be exacerbated by thealuminum chuck having to continuously move up and down (e.g., to loadand unload each new wafer) within the bowl. That is, as the chuck movesup and down within the bowl, some of its coating may flake off of thechuck, thus generating particulates and contaminants inside the bowl andthe SRD module. In some cases, these contaminants may react with theresidual chemicals (e.g., HF, NH₃OH, etc.) present in the SRD modulefrom previous brush scrubbing operations. It is believed that thesechemical reactions between the residual chemicals and the generatedparticulates and contaminants of the chuck may cause the recontaminationof the wafer as well as the SRD module.

In view of the foregoing, a need therefore exists in the art for anapparatus that controls and reduces the airflow to a backside of asubstrate during a spin, rinse, and dry operations. Additionally, thereis a need for a chemically compatible chuck assembly that improves thespin, rinse, and dry operations performed on the surfaces of substrateswhile reducing the risk of wafer recontamination.

SUMMARY OF THE INVENTION

Broadly speaking, the present invention fills these needs by providingan apparatus and related methods for optimizing the spin, rinse, and dryoperations of a spin, rinse, and dry (SRD) module. The SRD moduleimplements a wafer backside plate designed to control air turbulencearound a substrate so as to reduce recontamination to the under-surfaceof the substrate. Preferably, in one embodiment, reducingrecontamination to the under-surface of the substrate is achieved byplacing the top-surface of the wafer backside plate and theunder-surface of the substrate substantially on the same plane. In onepreferred implementation, the top-surface of the wafer backside plateand the under-surface of the substrate are placed on the substantiallysame plane by a chuck assembly rotating at high RPMs, thus throwing thewafer backside plate to an up position.

It should be appreciated that the present invention can be implementedin numerous ways, including as a process, an apparatus, a system, adevice, or a method. Several inventive embodiments of the presentinvention are described below.

In one embodiment, a method for spinning a wafer to enable rinsing anddrying is provided. The method includes engaging the wafer at a waferprocessing plane and spinning the wafer. The method further includesmoving a wafer backside plate from a first position to a second positionas spinning of the wafer proceeds to an optimum spinning speed. Thesecond position defines a reduced gap between an under surface of thewafer and a top surface of the wafer backside plate. The method alsoincludes repositioning the wafer backside plate from the second positionto the first position as the spinning reduces in speed. The firstposition defines an enlarged gap to enable loading and unloading of thewafer from the engaged position.

In another embodiment, another method for spinning a wafer to enablerinsing and drying is provided. The method includes engaging the waferat a wafer processing plane and spinning a wafer backside plate definedbelow the wafer processing plane. The wafer backside plate is moved froma first position to a second position as the spinning of the waferproceeds to an optimum spinning speed. The second position defines areduced gap between an under surface of the wafer and a top surface ofthe wafer backside plate. The method further includes repositioning thewafer backside plate from the second position to the first position asthe spinning reduces in speed. The second position defines an enlargedgap to enable loading and unloading of the wafer from the engagedposition.

In yet another embodiment, still another method for spinning a wafer toenable rinsing and drying is provided. The method includes providing thewafer over a process bowl and engaging the wafer at the processingplane. The method further includes spinning the wafer and the waferbackside plate defined below the wafer processing plane. The waferbackside plate is raised from a lower position to an upper position asspinning of the wafer proceeds to a process spinning speed. The upperposition defines a reduced gap between an under surface of the wafer anda top surface of the wafer backside plate. Also included in the methodis lowering the wafer backside plate from the upper position to thelower position as the spinning reduces in speed. The lower positiondefines an enlarged gap to enable loading and unloading of the waferfrom the engaged position.

In still another embodiment, yet another method for spinning a wafer toenable rinsing and drying is provided. A wafer is provided over aprocess bowl and is engaged at a wafer processing plane. The wafer and abackside plate defined below the wafer processing plane are spun. Thewafer backside plate is raised from a lower position to an upperposition as the spinning of the wafer proceeds to a process spinningspeed. The upper position defines a reduced gap between an under surfaceof the wafer and a top surface of the wafer backside plate. The reducedgap is designed to reduce turbulent airflow under the wafer. The waferbackside plate is lowered from the upper position to the lower positionas the spinning reduces in speed. The lower position defines an enlargedgap to enable loading and unloading of the wafer from the engagedposition. The wafer is disengaged and removed from over the processbowl. The operations are repeated for all additional wafers.

In still another embodiment, an apparatus for preparing a wafer isprovided. The apparatus includes a wafer backside plate and a centralshaft. The wafer backside plate has a top surface that includes acylindrical edge lip, which defines a central aperture. The centralshaft is designed to fit within the central aperture. The wafer backsideplate is configured to automatically slide between an up position duringrotational wafer processing and a down position when the wafer is not inrotational wafer processing. A gap defined between the top surface ofthe wafer backside plate and the wafer is less when the wafer backsideplate is in the up position than when the wafer backside plate is in thedown position.

In yet another embodiment, an apparatus for preparing a wafer isprovided. The apparatus includes a chuck having a plurality of grippersfor holding the wafer, a wafer backside plate, and a shaft. The waferbackside plate has a top surface and includes a cylindrical edge lipthat defines a central aperture. The shaft is connected to a centralportion of the chuck and is configured to receive and engage the centralaperture of the backside plate. The wafer backside plate is configuredto automatically slide between an up position during rotational waferprocessing and a down position when completing rotational waferprocessing. A gap defined between the top surface of the wafer backsideplate and the wafer is less when the wafer backside plate is in the upposition than when the wafer backside plate is in the down position.

In yet another embodiment, an apparatus for spinning, rinsing and dryinga wafer is provided. The apparatus includes a chuck, a wafer backsideplate, and a shaft. The chuck has a plurality of wafer holders forholding the wafer during the spinning, rinsing and drying. The waferbackside plate has a disk-like top surface that mirrors the wafer beingheld by the holders above the wafer backside plate. The wafer backsideplate includes a cylindrical edge lip at a center that has an innersurface, which defines a central aperture. The shaft is connected to acentral portion of the chuck and is configured to receive and engage thecentral aperture of the backside plate. The wafer backside plate isconfigured to automatically slide between an up position duringrotational wafer processing and a down position when completingrotational wafer processing. A gap defined between the top surface ofthe wafer backside plate and the wafer is less when the wafer backsideplate is in the up position than when the wafer backside plate is in thedown position.

The advantages of the wafer backside plate of present invention arenumerous. Most notably, unlike the conventional fixed wafer backsideplates, the wafer backside plate of the present invention is liftableand is configured to move between up and down positions. Thus, theliftable wafer backside plate reduces recontamination to theunder-surface of the substrate by placing the top-surface of the waferbackside plate and the under-surface of the substrate to be processed ona substantially same plane during the spinning operations. Accordingly,the embodiments of the present invention improve the quality of thespin, rinse, and dry operations of the SRD module while substantiallysimultaneously increase the overall throughput of the SRD module.

Other aspects and advantages of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings, illustrating by way of example the principles ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be readily understood by the followingdetailed description in conjunction with the accompanying drawings, andlike reference numerals designate like structural elements.

FIG. 1 is an isometric view of a chuck body and a chuck top plate of achuck assembly, in accordance with one embodiment of the presentinvention.

FIG. 2A is an isometric view of a fully put together chuck assembly in aclosed position, in accordance with one embodiment of the presentinvention.

FIG. 2B is an isometric view of a fully put together chuck assembly in aclosed position including a wafer backside plate, in accordance withanother embodiment of the present invention.

FIG. 3 is a schematic A-A cross-sectional view of the chuck assembly andwafer backside plate depicted in FIG. 2B, in accordance with yet anotherembodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a closed chuck assemblyand a wafer backside plate as the chuck assembly assumes an openposition, in accordance with still another embodiment of the presentinvention.

FIG. 5 is an exploded, partial cross-sectional view of a closed chuckassembly and a wafer backside plate, illustrating the individualcomponents and the manner in which the components fit together toconstruct the chuck assembly, in accordance with one embodiment of thepresent invention.

FIG. 6A is an isometric view of a wedge assembly as it assumes a lowerposition, in accordance with one aspect of the present invention.

FIG. 6B is an isometric view of a wedge assembly as it assumes an upperposition, in accordance with yet another aspect of the presentinvention.

FIG. 6C is an isometric view of a wedge assembly implementing a key, inaccordance with another aspect of the present invention.

FIG. 7A is an exploded, schematic, cross-sectional view of a wedgeassuming a lower position, in accordance with still another aspect ofthe present invention.

FIG. 7B is a top view of a manifold having a plurality of ports, inaccordance with yet another aspect of the present invention.

FIG. 8A is a simplified, schematic, cross-sectional view of a closedchuck assembly having a gripper in a substantially upright position, inaccordance with another embodiment of the present invention.

FIG. 8B is a simplified, schematic, cross-sectional view of an openchuck assembly having a gripper in a substantially flat position, inaccordance with yet another embodiment of the present invention.

FIG. 9A is a simplified, schematic, cross-sectional view of a chuckassembly gripper, in accordance with yet another aspect of the presentinvention.

FIG. 9B is a simplified, schematic, cross-sectional view of a chuckassembly roller, in accordance with still another aspect of the presentinvention.

FIG. 10 is an isometric view of a chuck body of a chuck assembly in aclosed position, in accordance with yet another embodiment of thepresent invention.

FIG. 11 is an isometric view of a fully put together chuck assembly anda wafer backside plate with the chuck assembly being in a closedposition, in accordance with still another embodiment of the presentinvention.

FIG. 12 is a cross-sectional view of the chuck assembly and the waferbackside plate illustrated in FIG. 11, in accordance with one embodimentof the present invention.

FIG. 13 is an enlarged, partial, cross-sectional view of a chuckassembly in an open position with a wafer backside plate, in accordancewith yet another embodiment of the present invention.

FIG. 14 is a cross-sectional view of a closed chuck assembly with abackside plate in a down position, in accordance with still anotherembodiment of the present invention.

FIG. 15 is a cross-sectional view of a closed chuck assembly with awafer backside plate in an up position, in accordance with still anotherembodiment of the present invention.

FIG. 16 is an exploded cross-sectional view a wafer backside plate and asleeve having a height adjusting slot depicting the manner in which thebackside plate pins work in conjunction with height adjusting slots tofunction as wafer backside plate motion stoppers, in accordance with yetanother embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Embodiments of a spin, rinse and dry module (SRD) and a wafer backsideplate for use in an SRD module for optimizing the spin, rinse and dryoperations performed on substrate surfaces while minimizing thepossibility of wafer under-surface recontamination are described.Preferably, the SRD module implements a liftable wafer backside plateconfigured to be moved between up and down positions. In one exemplaryembodiment, recontamination to the under-surface of the substrate isreduced by placing the top surface of the wafer backside plate and theunder-surface of the substrate on the same plane. In one preferredimplementation, the wafer backside plate is moved from its initial downposition to the up position as a result of centrifugal force created bythe increasing RPMs of a rotating chuck assembly. Preferably, in oneexample, the wafer backside plate is connected via wafer backside pinsto a sleeve defined in a wedge contained within the chuck assembly. Thewafer backside pins and the height adjusting slots defined on the sleeveare configured to collectively act as wafer backside plate motionstoppers. Preferably, the wafer backside plate is designed to controlair turbulence around a substrate so as to reduce recontamination to theunder-surface of the substrate.

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill be understood, however, to one skilled in the art, that the presentinvention may be practiced without some or all of these specificdetails. In other instances, well known process operations have not beendescribed in detail in order not to unnecessarily obscure the presentinvention.

For ease of understanding, a detailed description of the chuck assemblywill be provided in Section 1, and a detailed description of the waferbackside plate will be provided in Section II.

I. Chuck Assembly:

FIG. 1 is an isometric view of a chuck body 102 and a chuck top plate110 of a chuck assembly 100, in accordance with one embodiment of thepresent invention. As shown, the chuck body 102 is in the shape of acylindrical disk, as the cylindrical shape advantageously createssubstantially less air disturbance in the SRD module, thus improvingairflow around the substrate surface. In an exemplary embodiment, theinertia of the cylindrical chuck assembly 100 is reduced by forminghogged-out regions 102 a within the chuck body 102. By way of example,the hogged-out regions 102 a may be formed by machining out specificinner portions of the chuck body 102. As a result of forming thehogged-out regions 102 a, the weight of the chuck body 102 is reduced,thus enabling the use of substantially less amount of energy to rotatethe chuck assembly 100, thereby allowing the use of a substantiallysmaller motor (not shown in the Figure).

As shown, the exemplary embodiment of FIG. 1 includes 3 hogged-outregions 102 a defining spokes 102 f, a chuck outer ring 102 b and achuck inner ring 102 c. The spokes 102 f are configured to extend fromthe chuck outer ring 102 b to the chuck inner ring 102 c. Each of thespokes 102 f is further configured to house a linkage arm 112 having alength substantially equivalent to the length of its respective spoke102 f. Each of the linkage arms 112 has an outer end and an inner endand is configured to cause the respective gripper 112 to move betweenopen/close positions, as a wedge 106 moves between a lower position andan upper position. In one implementation, the wedge 116 may be aconical-type wedge. As depicted, the wedge 106 is defined within thechuck inner ring 102 c of the chuck 102 and is designed to exert tensionon each of the linkage arms 112 and the respective gripper 112 as thewedge 106 moves between an upper position and a lower position. In oneembodiment, as shown in FIG. 1, this tension is created by springloading each of the linkage arms 112 by nesting a segment of each of thelinkage arms 112 within a spring 104. However, it must be noted thatalthough in this embodiment a spring has been implemented to create suchtension, it must be understood by one of ordinary skilled in the artthat any appropriate mechanism may be used.

Further shown in FIG. 1 are chuck body gripper motion slots 120 e, whichare configured to allow each of the grippers to pivot about a respectiverotation pin 120 (not shown in this Figure). In one embodiment, when thewedge 106 is in the upper position, each of the grippers 112 pivot aboutthe respective rotation pin 120 and is moved backward such that thegrippers lay almost parallel to the chuck top plate 110. However, whenthe wedge 106 moves down to the lower position, the grippers 112 areconfigured to rotate about the respective rotation pin 120 in the chuckbody gripper motion slot 102 e so as to assume an upright position.Additional details regarding the wedge 106, the grippers, the chuckassembly 100, and their mechanisms are set forth below in connectionwith the descriptions of FIGS. 2-9B.

Further included in FIG. 1 is the chuck top plate 110, which in thisimplementation, is configured to be in the shape of a cylindrical platecover. The chuck top plate 110 will thus isolate the moving parts of thechuck body 102 from the wafer, and reduce potential contamination fromparticulates generated by moving parts. The chuck top plate 110 includesa plurality of chuck top plate gripper motion slots 110 b, each designedto enclose a respective gripper 112. As depicted, the chuck top plate110 is configured to be secured to the chuck body 102 by way of aplurality of fastening holes 110 d designed on the chuck top plate 110such that their positions are over a plurality of joining holes 102 dwhich are formed around the inner ring 102 c of the chuck body 102.Screws, not shown, are then attached through the fastening holes and thejoining holes 102 d. Further shown is a chuck top plate bore 111 that isconfigured to engage a manifold 116 located within a wedge 106.

As shown, the wedge 106 is to include a central throughbore 126. In oneimplementation, the throughbore 126 is designed to hold a sleeve 128(not shown in this Figure) configured to contain fluid delivery tubes.The fluid delivery tubes are formed in the manifold 116. The manifold116 has a plurality of ports 116 a, 116 b, and 116 c designed to deliverfluids to a backside of a wafer. In one embodiment, the presence of thewafer is configured to be detected through a use of a wafer presencesensor 130 defined at about the center of the manifold 116.

Preferably, unlike the conventional chucks wherein the chuck body movesup and down within the process bowl, in the present invention, ratherthan the chuck body 102, the wedge 106 has been designed to verticallymove within the chuck assembly 100. Thus, advantageously, the chuckassembly 100 is designed to remain at a fixed height. In this manner,unlike prior art chucks which use the vertical movement of the chuckitself to load/unload the wafer, the embodiments of the presentinvention utilize the vertical movement of the wedge 106 to cause thegrippers to engage/disengage the wafer to be processed. Consequently,the present invention has several advantages over the prior art. First,as the chuck body 102 remains at a fixed height, unlike the prior artSRD module, the present invention eliminates the problems associatedwith the necessity of designing a complex chuck. Second, as the chuckbody 102 remains in place horizontally, the chuck assembly 100 does notintroduce further contaminants and particulates into the SRD bowl. Inone embodiment, the SRD bowl 202 may be a bowl as described in U.S.patent application Ser. No. 09/470,676, filed on Dec. 23, 1999, havinginventors Roy Winston Pascal and Brian M. Bliven, and entitled “Bowl,Spin, Rinse, and Dry Module, and Method for Loading a SemiconductorWafer into a Spin, Rinse, and Dry Module.” This U.S. Patent Application,which is assigned to Lam Research Corporation, the assignee of thesubject application, is incorporated herein by reference.

FIG. 2A is an isometric view of a chuck assembly 200 in a closedposition, in accordance with one embodiment of the present invention. Asshown, a fully assembled chuck 200 includes a chuck body 102 connectedto a chuck top plate 110. The chuck body 102 and the chuck top plate 110are both configured to be in the shape of a cylindrical disk. Asdiscussed with regards to FIG. 1, the chuck top plate 110 includes achuck top plate bore 111 and a contiguous cylindrical ring 111′ definedat about the center of the chuck top plate bore 111. As shown, when thechuck top plate 110 is placed over the chuck body 102, the chuck topplate 110 hides the wedge 106. Furthermore, when the wedge 106 is in theup position, the chuck top plate 110 is positioned such that a small gapexists between the wedge top surface 106 c of the wedge 106 and thechuck top plate 110. However, when the wedge 106 is in the downposition, a larger gap exists between the chuck top plate 110 and thewedge top surface 106 c of the wedge 106. In one exemplary embodiment,the top surface 110 a of the chuck top plate 110 is placed on top of thechuck body 102 such that the chuck top plate 110 is defined below thewafer process plane.

A plurality of grippers 112 are coupled to the chuck body 102 and areconfigured to pivot about the respective rotation pins 120 (not shown inthis drawing). The grippers 112 are further configured to protrude abovethe top surface 110 a of the chuck top plate 110 and chuck top plategripper slots 110 b. As shown in the embodiment of FIG. 2A, when thechuck assembly 200 is in the closed position, the grippers areconfigured to assume an upright position so as to engage the wafer to beprocessed. The chuck top plate gripper slots 110 b as well as the chuckbody gripper slots are configured to facilitate the pivotal movement ofthe grippers. The advantage of implementing grippers capable of assumingboth upright and flat positions is that the grippers 112 cansubstantially pivot about the rotation pin (or other mechanism) so as toassume a position that is substantially parallel to the chuck top plate110. This is beneficial as it eliminates additional mechanical movementsrequired in loading and unloading of the chuck, as the end effector isno longer required to be raised above the gripper to load/unload thewafer. This is achievable because the grippers 112 no longer block theend effector as it loads/unloads the wafer, because in the openposition, the grippers 112 lay flat.

The chuck top plate 110 is configured to be clamped to the chuck body102, thereby sealing the linkage mechanism within the chuck assembly200. In another example, the chuck body 102 may be fastened to aspindle. However, it must be appreciated by one of ordinary skill in theart that any appropriate fastening mechanism may be used to fasten thechuck body 102 to the chuck top plate 110.

Also shown is a wafer backside plate 114 configured to be positionedover the top surface 110 a of the chuck top plate 110. As illustrated,the wafer backside plate 114 is configured to have a central hole 114 aand a contiguous cylindrical edge 114 b defined around the central hole114 a. The wafer backside plate 114 is configured to reducerecontamination to the backside of the wafer being processed.

In one implementation, the chuck body 102, the top surface 110 a of thechuck top plate 110, the grippers 112, and the wafer backside plate 114are constructed from Teflon™. However, it must be appreciated by one ofordinary skill in the art that the chuck body 102, the chuck top plate110, the grippers 112, and the wafer backside plate 114 may beconstructed from any chemically inert material (e.g., Hastalloy, HighSpeed Enchanted Plastic, Turchite, Polypropylene, PET, PEEK, VESPEL,DURALON, Teflon, etc.) This is beneficial because unlike conventionalSRD modules which implement incompatible components thus causing modulerecontamination, most of the components of the chuck assembly 200 of thepresent invention are constructed from chemically inert materials thuspreventing introduction of almost any recontaminants into the SRDmodule.

The contiguous cylindrical lip 114 b of the wafer backside plate 114 isconfigured to enclose a manifold 116, as the manifold 116 protrudesabove the top surface 106 c of the wedge 106. Accordingly, in preferredembodiments, a radius of manifold 116 is configured to be less than aradius of the contiguous cylindrical lip 114 b of the wafer backsideplate 114, which in turn, is less than a radius of the contiguouscylindrical ring 111′ of the chuck top plate 110. The manifold 116includes a plurality of ports such as ports 116 a, 116 b, and 116 c eachdesigned to receive a fluid delivery tube. In one exemplary embodiment,different fluid may be delivered to each of the ports 116 a-116 c (e.g.,DI water, HF, NH₃OH, nitrogen, CDA, non-residual cleaning solvents,etc.). In addition to the ports 116 a-c, the manifold 116 is configuredto include a wafer presence sensor 130. Additional details regarding thechuck assembly, gripper design, the manifold, and their mechanisms areset forth below in connection with the description of FIGS. 3-9B.

FIG. 2B is an isometric view of a fully put together chuck assembly 200′in a closed position as it includes a wafer backside plate 114, inaccordance with one embodiment of the present invention. As illustrated,the wafer backside plate 114 is placed over a chuck top plate 110 suchthat the wafer backside plate is substantially in the same horizontalplane as a manifold 116 and below a wafer process plane. By having thechuck top plate 110 and the wafer backside plate 114 below the waferprocess plane, several mechanical movements in loading and unloading ofthe wafer can be eliminated, thus increasing the overall throughput ofthe SRD module. For instance, because the grippers 112 have thecapability to pivot about the respective rotation pins 120 toload/unload a wafer, they simply assume a flat position during theloading/unloading of the wafer. That is, when the grippers 112 aresubstantially flat, the end effector can easily load/unload the wafer tothe grippers without first having to be raised above the wafer processplane. For instance, in one embodiment, to deliver a wafer, the grippersare first placed in the open/flat position. Then, the end effectordelivers the wafer substantially in the same level as the wafer processplane. Thereafter, the grippers 112 are placed in an upright/closedposition, thus engaging the wafer. Although in this embodiment an endeffector has been used to load/unload wafer 118, it must be appreciatedby one of ordinary skill in the art that other equivalent mechanism maybe utilized so long as the function of loading and unloading the wafer118 to the grippers 112 is achieved.

A schematic A-A cross-sectional view of the chuck body 200′ of FIG. 2Bis depicted in FIG. 3, in accordance with another embodiment of thepresent invention. As shown, each of the linkage arms 122 is coupled toa respective gripper 112 with a respective linkage pin 122 a, and eachof the grippers 112 is coupled to a chuck body 102 using a respectiverotation pin 120. Each of the grippers 112 is configured to rotate aboutthe respective rotation pin 120 while the rotation pins 120 areconfigured to be substantially fixed. Although in this embodiment arotation pin 120 is used to couple each of the grippers 112 to the chuckbody 102, it must be noted that in a different embodiment, any otherappropriate mechanism may be used to couple the gripper 112 to the chuckbody 102.

Also shown in the embodiment of FIG. 3 is a chuck top plate 110 placedabove the chuck body 102 and a wafer backside plate 114 as it is definedabove the chuck top plate 110. Further depicted are the contiguouscylindrical ring 111′ of the chuck top plate 110 as well as thecontiguous cylindrical lip 114 b of the wafer backside plate 114.

Each of the linkage arms 122 is configured to move substantiallyhorizontally, thus exerting tension on the wedge 106 via a respectivespring 104. In this embodiment, each of the springs 104 is shelvedwithin the chuck body 102 without actually being connected to the chuckbody 102 or the respective linkage arm 122. As shown, the tension steps122 b may be designed to a particular size to prevent each of the spring104 from exerting excessive pressure onto a wedge sidewall 106 e of thewedge 106. In one exemplary implementation, the tension created by eachof the springs 104 is used to maintain the surface of the respectivelinkage arm 122 against the wedge sidewall 106 e.

Further shown in the embodiment of FIG. 3 is a central throughbore 126formed in the wedge 106. The wedge 106 is solid core and has athroughbore 126 that extends from a wedge bottom surface 106 d to thewedge top surface 106 c. Preferably, as the wedge 106 moves from a lowerposition to an upper position, the wedge 106 applies less pressure ontothe linkage arms 122, which in turn, apply less pressure to therespective spring 104 and ultimately, to the respective spring step 122b. This decrease in exerted pressure on the linkage arms 122 furtherreduces the amount of pressure applied to the linkage pins 122 a and thegrippers 112, thus causing each of the grippers 112 to pivot about therespective rotation pin 120. Consequently, each of the grippers 112pivots backward about the respective rotation pin 120 so as to assume anopen/flat position, thus disengaging the wafer 118.

However, as the wedge 106 moves from the upper position to the lowerposition, due to the shape of the wedge 106, gradually, the radii of thepoint of contacts of the linkage arms 122 and the wedge sidewall 106 eincreases, thus increasing the amount of pressure applied to each of thelinkage arms 122 and consequently, the respective spring 104 and therespective linkage pin 122 a. As a result of this increase in pressure,each of the grippers 112 is pivoted forward about the respectiverotation pin 120 so as to assume an upright/closed position, thusengaging the wafer 118. As shown in the embodiment of FIG. 3, a gapexists between the wedge top surface 106 c and the chuck top plate 110allowing the wedge 106 to freely move between the lower position and theupper position.

FIG. 4 is a schematic cross-sectional view of a closed chuck assembly asit transitions to an open position, in accordance with one embodiment ofthe present invention. As shown, a wafer backside plate 114 ispositioned above a chuck top plate 110, which in turn is placed above achuck body 102. A linkage arm 122 is coupled to a gripper 112 with alinkage pin 122 a, as a spring 104 is used to create tension between thelinkage arm 122 and a wedge sidewall 106 e. Thus, for a gripper 112 toassume an open/flat position, the linkage arm 122 is configured to movein a movement direction 122 c. In one embodiment, the movement direction122 c is configured to be a movement in the horizontal direction.

As depicted, the wedge 106 includes a throughbore 126 extending from awedge lower surface 106 d to the wedge top surface 106 c. As shown, asleeve 128 is fed through the throughbore 126 such that the sleeve 128protrudes above the chuck top plate 110 to be flush with the level asthe wafer backside plate 114. A manifold 116 is inserted into the sleeve128 and is fitted within a sleeve outlet 128 a such that the manifold116 is also defined within the same level as the wafer backside plate114. The manifold 116 includes a wafer sensor presence 130 used todetect the presence of the wafer 118 as well as ports 116 a and 116 bimplemented to deliver fluid onto the backside of a wafer 118.

As shown, the gripper 112 is assuming an open/flat position as the wedge106 is moving to an upper position. That is, as the wedge 106 is movingupwardly, the radius of the wedge 106 at the point of contact of thelinkage arm 122 and the wedge sidewall 106 e decreases, thus placingless pressure onto the linkage arm 122 and the spring 104. As a result,the wedge 106 pulls on the linkage arm 112, thus decreasing the pressureapplied onto the linkage pin 122, thus causing the gripper 112 to pivotback so as to disengage the wafer 118. At this point, an end effectorblade 117 is holding the wafer 118. Additional details with respect tothe wedge 106, the wedge mechanism, the manifold 116, the grippers 112,and the chuck mechanism are set forth below in connection with FIGS.5A-9B.

FIG. 5 is an exploded cross-sectional view of a closed chuck assemblyillustrating the individual components of the chuck assembly and themanner in which the components fit together to construct the chuckassembly, in accordance with one embodiment of the present invention. Asshown, the manifold 116 is inserted into the sleeve outlet 128 a as asleeve 128 is fed into the throughbore 126 of the wedge 106. The wedge106 is in turn defined within a chuck body 102 such that linkage arms122 and 122′ come into contact with the wedge sidewall 106 e, as thewedge 106 moves between an upper position and a lower position withinthe chuck assembly 200. A Chuck top plate 110 having a cylindricalcontiguous cylindrical ring 111′ is defined on top of the chuck body 102such that a gap is defined between the chuck top plate 110 and the wedgetop surface 106 c. This gap exists to accommodate the vertical movementsof the wedge 106 within the chuck body 102. A wafer backside plate 114is defined on top of the chuck top plate 110. As shown, the sleeve 128is fed through the throughbore 126, the contiguous cylindrical ring 111′of chuck top plate 110, and the contiguous cylindrical lip 114 b of thewafer backside plate 114 such that the manifold 116 is defined withinsubstantially the same horizontal plane as the wafer backside plate 114and below the wafer process plane.

FIG. 6A is an isometric view of a wedge assembly 600 as it assumes alower position, in accordance with one embodiment of the presentinvention. A wedge 106 includes a wedge top surface 106 c, a bottomsurface 106 d, and a wedge sidewall 106 e. In one implementation,channels 150 a and 150 b may be defined substantially parallel to thewedge sidewall 106 e so as to allow respective linkage arms 122 and 122′to move along the wedge sidewall 106 e, from an upper position to alower position and from a lower position to an upper position, as thewedge 106 moves upwardly and downwardly in a movement direction 140.

As shown, a linear drive shaft 134 is configured to be coupled to thewedge bottom surface 106 d and is designed to define the diameter of athroughbore 126 defined within the wedge 106. The linear drive shaft 134is configured to move the wedge 106 up and down in the movementdirection 140 as the linear driver shaft 134 rotates in the rotationdirection 138, thus causing the chuck assembly to assume an open or aclosed position. Additionally, the linear drive shaft 134 is definedwithin a rotary drive shaft 132 and in one embodiment, is coupled to therotary drive shaft 132 via pins 136. The rotary drive shaft 132 isdesigned to be substantially fixed in the X, Y, and Z-axes as it rotatesin the rotation direction 138. Accordingly, the linear drive shaft 134as well as the rotary drive shaft 132 are configured to rotate in therotation direction 138. In one exemplary embodiment, the linear driveshaft 134 and rotary drive shaft 132 are configured to be constructedfrom substantially the same material (e.g., 300 series stainless steel,Hastalloy, Titanium, Aluminum, etc.).

As shown, a sleeve 128 is defined within the linear drive shaft 134 soas to protect the fluid delivery tubes (now shown) from the movements ofthe linear drive shaft 134. However, it must be understood by one ofordinary skill in the art that although in this embodiment the sleeve128 has been implemented to protect the fluid delivery tubes from therotational movement of the linear drive shaft 134, in a differentembodiment, other isolation techniques may be used so long as the fluiddelivery tubes are protected.

The relationship of the linear drive shaft 134 and the rotary driveshaft 132 can further be understood with reference to FIG. 6B. As shown,while the linear drive shaft 134 is configured to be coupled to thewedge 106, the rotary drive shaft 132 is not. Accordingly, at somepoints in time, as the wedge 106 is moving between an upper position anda lower position in a movement direction 140, so does the linear driveshaft 134. However, as shown, in such instances, the rotary drive shaft132 is maintained at a fixed height. This occurs because the rotarydrive shaft 132 is not coupled to the wedge bottom surface 106 d.

Although in the embodiments of FIGS. 6A and 6B the wedge 106 areconfigured to include channels 150 and 150′ to facilitate the movementof the linkage arm 122 along the wedge sidewall 106 e, it must beunderstood by one of ordinary skill in the art that any appropriatemechanism capable of facilitating the movement of the linkage arm 122along the wedge sidewall 106 e may be used instead of the channels 150and 150′ (e.g., keyways, surface to surface contact slide mechanisms,etc.) Furthermore, it must be noted that in one exemplary embodiment,one may choose not to implement any of such mechanisms on the wedgeassembly 600′.

For instance, as shown in the embodiment of FIG. 6C, instead ofimplementing a channel, a linkage arm 122 may be placed in contact witha wedge 106 via a keyway 151 coupled to a wedge 106 between points 151 aand 151 b. As shown, in the embodiments wherein the keyway 151 is used,there may not be a need to use a spring. Thus, in the instances whereinthe wedge 106 is in the upper position, the linkage arm 122 contacts thekeyway 151 at the point 151 c, defined at about the upper part of thekey 151. However, as the wedge 106 moves down to assume the lowerposition, the linkage arm 122 moves along the keyway 151 until itreaches almost the lower part of the key 151.

FIG. 7A is an exploded schematic cross-sectional view of a wedge 106assuming an upper position, in accordance with one embodiment of thepresent invention. A wedge 106 includes a throughbore 126, which extendsfrom a wedge bottom surface 106 d to a wedge top surface 106 c. A sleeve128 is fed through the throughbore 126 such that the sleeve 128protrudes above the wedge top surface 106 c and above the chuck topplate 110. Preferably, the sleeve 128 is configured to be almost in thesame level as the wafer backside plate 114 (not shown in this Figure),which is configured to be defined above the chuck top plate 110. Amanifold 116 is inserted into the sleeve outlet 128 a of the sleeve 128and is configured to include a plurality of drilled ports 116 a and 116b designed to receive fluid delivery tubes 116 a′ and 116 b′. Alsoincluded in the manifold 116 is a wafer presence sensor 130.

As the wedge 106 moves upwardly to assume an upper position, the wedgesidewall 106 e is pushed against the linkage arm 122, thus causing thelinkage arm 122 to be moved along the wedge sidewall 106 e in themovement direction 150 a from a first position 122 a to a secondposition 122 b. As shown, a gap 107 is defined between the wedge topsurface 106 c and the chuck top plate 110 to prevent the wedge 106 fromcoming into contact with the chuck top plate 110 at the points in timethe wedge 106 is in the upper position.

FIG. 7B is a top view of a manifold 116 having a plurality of ports, inaccordance with one embodiment of the present invention. Preferably,fluids are delivered through tubes that fit in the ports 116 a-c so asto be implemented in the rinsing of the backside of the wafer 118. Inaddition to the ports 116 a-c, the manifold 116 is configured to includea wafer presence sensor 130 that is used to detect the presence of awafer.

FIGS. 8A and 8B are simplified schematic cross-sectional views of aclosed chuck assembly 800 and an open chuck assembly 800′, respectively,in accordance with one embodiment of the present invention. As shown inFIG. 8A, when a wedge 106 is in a lower position, a distance “d” betweena point of contact 122 b of a linkage arm 122 and a wedge sidewall 106 eand a throughbore sidewall 126 a is defined to be x. As illustrated, thedistance x represents the horizontal distance between the throughboresidewall 126 a and the point of contact 122 b. As shown, a gripper 112of FIG. 7A has assumed an upright position thus engaging a wafer 118.

Comparatively, in FIG. 8B in which the wedge 106 is in an upperposition, the distance “d′” between the point of contact 122 b′ of thelinkage arm 122′ and the wedge sidewall 106 e is defined to be d′ (i.e.,x-Δx). As shown, the distance d′ is the horizontal distance between thepoint of contact 122 b′ and a throughbore sidewall 126 a. Accordingly,as depicted, the distance d is configured to be greater than thedistance d′, thus causing the pressure exerted on the wafer linkage 122of FIG. 8A be greater than the pressure exerted on the wafer linkage122′ of FIG. 8B. As a result of this increase in exerted pressure on thelinkage arm 122, a greater pressure is being applied on the linkage pin122 a, thus causing the gripper 112 to assume an upright/closedposition. In contrast, as the wedge 106 moves up so as to assume anupper position, the amount of pressure exerted on the linkage 122′decreases, as the distance d′ decreases, thus applying less pressure onthe linkage pin 122 a′, causing the gripper 112′ to rotate about therotation pin 120 so as to assume a flat/open position.

FIGS. 9A and 9B are simplified schematic cross-sectional view of a chuckassembly gripper and a chuck assembly roller, in accordance with oneembodiment of the present invention. In one preferred embodiment, asdepicted in FIG. 9A, a gripper mouth 112″ is configured to have av-shape or an r-shape. That is, the gripper mouth 112″ is configured toengage a wafer 118 in substantially two points 112 a and 112 b, thusincreasing the tolerance of the gripper 112 as it engages/disengages thewafer 118. For instance, the wafer 118 may be configured to be wedgedbetween the two sloped faces of the gripper mouth 112″. In this manner,the gripper 112 is designed such that the gripper 112 controls thedirection of force being applied on to the wafer 118.

In one exemplary implementation, the chuck assembly may implement aroller assembly 113 to engage the wafer 118, which includes a rollerportion 113 a and a roller base 113 b. As shown in the embodiment ofFIG. 9B, the roller portion 113 a is configured to engage a wafer 118 intwo points 113 a ₁ and 113 a ₂ such that the roller portion 113 acontrols the amount of force placed on the wafer 118 while the wafer isengaged by the roller portion 113 a. In one embodiment, the rollerportion 113 a may be implemented such that it can rotate. Preferably,the grippers 112 and the rollers 113 are configured to be constructedfrom chemically inert materials (e.g., Teflon™, Hastalloy, EngineeredPlastics, stainless steel, etc.)

FIG. 10 is a simplified isometric view of a closed chuck assembly 1000,in accordance with another embodiment of the present invention. Thechuck assembly 1000 includes a chuck body 1102, which in this embodimentis in the shape of a cylindrical disc. The chuck body includes an outerring 1102 b and an inner ring 1102 c which are connected to one anothervia a plurality of spokes 1102 f. Further shown are a plurality ofhogged-out regions 1102 a defined between the adjacent spokes 1102 f.The hogged-out regions 1102 a are defined so as to reduce the inertia ofthe chuck assembly 1000 thus creating a chuck assembly having asubstantially less weight.

Each of the spokes 1102 f is configured to house a linkage arm 112, eachbeing substantially the same length as the respective spoke 1102 f. Inone exemplary embodiment, each of the linkage arms 112 uses a spring 104to create tension between the wedge 106 and the respective gripper 112.In one embodiment, a spring 104 is configured to enclose portions of thelinkage arms 112.

As illustrated, a wedge 106 is defined within the chuck inner ring 1102c and is configured to include an almost central throughbore 126. Thethroughbore 126 is designed to engage a sleeve, which holds a manifold116 having a plurality of ports 116 a, 116 b, and 116 c designed todeliver fluids to a backside of a wafer.

FIG. 11 is an isometric view of a put together chuck assembly 1100 in aclosed position, in accordance with one embodiment of the presentinvention. The assembled chuck 1100 includes the chuck body 1102 and thewafer backside plate 114 defined on top of the chuck body 1102. Asshown, the wafer backside plate 114 substantially hides a wedge 106.

Preferably, when the wedge 106 is in the upper position, the waferbackside plate 114 is positioned on a rim 1102′ (not shown in thisFigure) of the chuck body 1102 such that a small gap exists between thetop surface 1106 c of the wedge 106 and the wafer backside plate 114.However, this gap is greater when the wedge 106 is in the lowerposition. As shown, the wafer backside plate 114 is placed over thechuck body 1102 such that the wafer backside plate 114 is defined belowthe wafer process plane. As defined, the wafer backside plate 114 isconfigured to prevent introduction of contaminants to the backside ofthe wafer 118. The wafer backside plate 114 is configured to be acylindrical plate having an aperture 114 a designed to enclose amanifold 116, as the manifold 116 protrudes above the wedge top surface106 c of the wedge 106. Thus, to achieve this, a radius of manifold 116is configured to be less than the radius of the aperture 114 a of thewafer backside plate 114. Further shown in FIG. 11 are a plurality ofgrippers 112 coupled to the chuck body 1102 as they have assumed anupright/closed position.

A cross-section 12-12 of the chuck body 1000 of FIG. 11 is depicted inFIG. 12, in accordance with another embodiment of the present invention.The gripper 112 is coupled to the linkage arm 122 with the linkage pin122 a and to the chuck body 1102 using the rotation pin 120. In oneimplementation, the rotation pin 120 is configured to be substantiallyfixed as the gripper 112 rotates about the rotation pin 120. Using aspring 104, the linkage arm 122 is designed to exert tension on a wedgesidewall 106 e of a wedge 106 as the linkage arm 122 moves horizontally.A tension step 122 b is used to prevent the spring 104 from exertingexcessive tension onto a wedge sidewall 106 e of the wedge 106. That is,in one embodiment, the tension created by the spring 104 is used tomaintain the surface of the linkage arm 122 against the wedge sidewall106 e of the wedge 106.

Also shown in FIG. 12 is a wafer backside plate 114 as it is positionedabove a rim 1102′ of the chuck body 1102. The aperture 114 a of thewafer backside plate 114 encloses the manifold 116, as the manifold 116protrudes above the wedge top surface 106 c of the wedge 106.Accordingly, in the embodiment of FIG. 12, a radius of manifold 116 isshown to be less than the radius of the aperture 114 a of the waferbackside plate 114.

As illustrated, the wedge 106 is in a lower position, thus causing thegrippers 112 to assume an upright/closed position. Preferably, a gapexists between the wedge top surface 106 c of the wedge 106 and the rim1102′ of the chuck body 1102. As the wedge 106 moves from the upperposition to the lower position, the radii of the wedge sidewall 106 e atthe point of contacts to the wedge sidewall 106 e and the linkage arms122 increases, thus increasing the amount of pressure applied to thelinkage arms 122 and consequently, the springs 104 and the linkage pins122 a. This increase in pressure causes the grippers 112 to rotate aboutthe respective rotation pins 120 as they are being pushed forward,thereby engaging the wafer 118 in an upright position.

FIG. 13 is a schematic cross-sectional view of a closed chuck assemblyas it assumes an open position, in accordance with one embodiment of thepresent invention. As shown, the wedge 106 is in an upper position, asthe gripper 112 is assuming a position substantially parallel to that ofa wafer backside plate 114. As the wedge 106 moves upwardly, the radiusof a wedge sidewall 106 e at a point of contact of the linkage arm 122and the wedge sidewall 106 e decreases, thus placing less pressure onthe linkage arm 122 and the spring 104. As a result of this decrease inpressure, the linkage arm 122 is pulled forward, pulling the gripper 112back, thus causing the gripper 122 to assume a flat/open position,thereby disengaging the processed wafer.

II. Wafer Backside Plate:

Having the description of the chuck assembly in mind, FIG. 14 is across-sectional view of a chuck assembly 1400 in a closed position andhaving a backside plate in a down position, in accordance with oneembodiment of the present invention. As shown, the chuck assemblyincludes a chuck top plate 2110 defined on top of the chuck body 102.The chuck assembly 1400 includes a plurality of linkage arms 122,grippers 112, linkage pins 122 a, and rotation pins 120, with each ofthe grippers being coupled to the respective linkage arm via therespective linkage pin 122 a, while each of the grippers 112 is coupledto the chuck body 102 via the respective rotation pin 120. As shown,grippers 112 are configured to generally unction as substrate holders.

The wedge 106 defined within the chuck body 102 includes the centralthroughbore 126 and is configured to move between the upper position andlower position. The movement of the wedge 106 causes the grippers 112 toassume either the upright/closed position to engage the wafer 118, orthe flat/open position to disengage the wafer 118. A sleeve 2128 is fedinto the throughbore 126 defined within the wedge 106 and is configuredto be placed at the level of the wafer backside plate 2114. The sleeve2128 can be viewed as a shaft and is configured to include heightadjusting slots 2128 a (not shown in this Figure) to control thevertical movement of the wafer backside plate 2114. Additional detailsregarding the shape of the height adjusting slots 2128 a and theirfunction are set forth below in connection with the descriptions ofFIGS. 15 and 16.

The chuck top plate 2110 includes a cylindrical inner ring 2110 bdefined on a chuck top plate bore 2111, and a cylindrical outer ring2110 a defined at a circumference of the chuck top plate 2110. As shown,the inner ring 2110 b and the outer ring 2110 a are defined on the chucktop plate 2110 such that they face the wafer backside plate 2114. Thewafer backside plate 2114 includes a cylindrical edge lip 2114 b definedat on an aperture 2114 a of the wafer backside plate 2114. Preferably,the radius of the aperture 2114 a of the wafer backside plate 2114 isconfigured to be substantially smaller than the radius of the chuck topplate bore 2111 such that when the wafer backside plate 2114 is in adown position, the chuck ring 2110 b and the edge 2114 b of the waferbackside plate mate on a plane defined below the wafer process plane.

Further depicted in FIG. 14 are wafer backside pins 2129 defined on anouter sidewall 2114 b ₁ of the wafer backside plate 2114. By way ofexample, as the chuck assembly 1400 starts to rotate and the RPMs of thechuck assembly 1400 increases, the centrifugal force created by therotation of the chuck assembly 1400 causes the rotating wafer backsideplate 2114 to be lifted from its initial down position and be shifted tothe up position. As illustrated, when the wafer backside plate 2114 isin the down position, a gap exists between the wafer backside plate 2114and the under-surface 118 a of the wafer 118. That is, in the downposition, the wafer backside plate 2114 is defined below the wafer 118and the wafer process plane. This configuration is beneficial becausethe position of wafer backside plate 2114 does not prevent the endeffector from loading/unloading the wafer 118 to the grippers 112.

Preferably, the wafer backside pins 2129 in conjunction with heightadjusting slots 2128 a are configured to function as wafer backsideplate motion stoppers. As shown, in the down position, the waferbackside pins 2129 are defined at about the middle of that portion ofthe sleeve 2128 that protrudes above the top surface 106 c of the wedge106. More details with respect to the wafer backside pins 2129 and theheight adjusting slots 2128 a and their respective functions are setforth below in connection with the descriptions of FIGS. 15 and 16.

The mechanism of the wafer backside plate 2114 can further be understoodin view of FIG. 15 as it depicts a closed chuck assembly 1400 with thewafer backside plate 2114 being in the up position, in accordance withone embodiment of the present invention. As shown, grippers 112 aredefined in the upright position thus engaging the wafer 118 in the waferprocess plane. Preferably, at the outset, the chuck assembly 1400 startsrotating in a movement direction 138 at low RPMs. Gradually, the RPMs ofthe Chuck assembly 1400 increases until it reaches a specific level,which in one embodiment, may be identified as a drying speed. At thatpoint, the centrifugal force created by the rotary movement of the chuckassembly 1400 causes the wafer backside plate 2114 to rise to the upposition, as illustrated in FIG. 15.

As opposed to the embodiment of FIG. 14, in this embodiment, the waferbackside pins 2129 are in contact with the sleeve 2128 in contact pointslocated close to the sleeve outlet 2128 a. That is, as the waferbackside wafer 2114 shifts upwardly by the centrifugal forces, the waferbackside pins 2129 are lead through the respective height adjustingslots 2128 a so as to reach the sleeve outlet 2128 a.

As shown, the wafer backside plate 2114 is raised such that thetop-surface 2114′ of the wafer backside plate 2114 is nestled to theunder-surface 118 a of a wafer 118, as the wafer 118 is placed in thewafer process plane. That is, the top-surface 2114′ of the waferbackside plate 2114 and the under-surface 118 a of the wafer 118 aredefined within the same plane. Thus, in contrast to FIG. 14 wherein alarger gap existed between the wafer 118 and the wafer backside plate2114, in the view of FIG. 15, the gap made much smaller. Thus, in theembodiment of FIG. 15, the wafer backside plate 2114 is in position forprocessing the wafer 118. Furthermore, as the top-surface 2114′ of thewafer backside plate 2114 and the under-surface 118 a of the wafer 118are almost within the same plane while the SRD module is operating, theunder-surface 118 a of the wafer 118 turbulent airflows are reduced thusreducing the degree of potential recontamination.

FIG. 16 illustrates the conjunctive work of the backside plate pins andheight adjusting slots to function as wafer backside plate motionstoppers, in accordance with one embodiment of the present invention. Asshown, in this embodiment, wafer backside pins 2129 are defined close toa bottom wall 2114 b ₂ of the cylindrical edge lip 2114 b of the waferbackside plate 2114. Preferably, the wafer backside pins 2129 have acylindrical shape and are retractable. That is, retractable springs 2129a are implemented between the wafer backside pins 2129 and the outersidewall 2114 b ₁ of the edge 2114 b of the wafer backside plate 2114 soas to enable the wafer backside pins 2129 to retract into thecylindrical edge lip 2114 b of the wafer backside plate 2114. Althoughin this embodiment only one wafer backside pin 2129 is depicted, it mustbe noted that an identical wafer backside pin 2129 is defined on thecylindrical edge lip 2114 b in a substantially opposite and symmetricallocation.

Also shown in FIG. 16 is the sleeve 2128 having height adjusting slots2128 a. Preferably, the height adjusting slots 2128 a are curvedchannels carved into the sleeve 2128 such that the height adjustingslots 2128 extend between a height A and a height B. Thus, in oneexample, the wafer backside pin 2129 is inserted into the heightadjusting slot 2128 a through a point 2128 c and is lead through theheight adjusting slots 2128 a until it reaches a point 2128 _(b),defining the end of the height adjusting slots 2128 a. That is, when thewafer backside plate 2114 is initially placed in its position (i.e.,over the chuck top plate 2110) the wafer backside pin 2129 is insertedinto the height adjusting slot 2128 at the point 2128 c defined at theheight A. It must be noted that although in this implementation only onewafer height adjusting slot 2128 a is shown, a matching wafer heightadjusting slot 2128 a is defined on the sleeve 2128 in a substantiallyopposite and symmetrical location.

In one embodiment, the mechanism of the wafer backside plate 2114 can bedescribed as follows: Initially, the wafer backside plate 2114 is in thedown position (i.e., the wafer backside plate 2114 is placed on top ofthe chuck top plate 2110). Then, the chuck assembly and the waferbackside plate 2114 start rotating at low RPMs. As the RPMs of the chuckassembly increase so as to reach a drying speed, the centrifugal forcecreated by the rotation of the chuck assembly causes the rotating waferbackside plate 2114 to rise from its initial down position. While therotating wafer backside plate 2114 is rising from the down position(i.e., position C) to assume the up position (i.e., position D), thewafer backside pin 2129 is lead through the height adjusting slot 2128 afrom the initial height A to the height B. Once the wafer backside plate2114 rises to the up position, at that point, the top surface of thewafer backside plate 2114 will almost be in the same plane as theunder-surface of the wafer. Having the top surface of the wafer backsideplate 2114 in the same plane as the wafer under-surface 118 a isadvantageous, as it reduces turbulent airflows under and over the wafer.An additional benefit is that it assists in reducing recontamination ofthe under-surface of the wafer 118 during drying operations.

However, as the RPMs of the chuck assembly decreases, the backside pin2129 of the wafer backside plate 2114 traverses back through the heightadjusting slot 2128 a from the height B to the height A so as to assumethe down position. Having a wafer backside plate 2114 configured to bemove from the up position to a down position is beneficial as the gapbetween the wafer backside plate 2114 and the wafer 118 allows the endeffector to approach the wafer process plane so as to load/unload aprocessed wafer.

Although in these embodiments the height adjusting slots 2128 a havebeen defined on the sleeve 2128 and the wafer backside pins have beendefined on the wafer backside 2114, it must be understood by one ofordinary skill in the art that in a different embodiment, the positionsof the wafer backside pins 2129 and the height adjusting slots 2128 amay be switched. That is, pins may be defined on the sleeve 2128 andheight adjusting slots may be defined on the wafer backside plate 2114so long as collectively, the pins and the height adjusting slots can actas wafer backside plate motion stoppers. Furthermore, it must be notedthat in the embodiments wherein the height adjusting slots 2128 a aredefined on the sleeve 2128, the sleeve 2128 may be constructed from amaterial flexible enough to endure the movement of the pins 2129 throughthe height adjusting slots 2128 a.

Although the foregoing invention has been described in some detail forpurposes of clarity of understanding, it will be apparent that certainchanges and modifications may be practiced within the scope of theappended claims. For example, embodiments described herein have beenprimarily directed toward spinning, rinsing, and drying (SRD) wafers;however, it should be understood that the SRD module of the presentinvention is well suited for spin rinsing of any type of substrate.Furthermore, it should be understood that the SRD module of the presentinvention is well suited for spin rinsing of any size wafer orsubstrate, such as hard disks. Accordingly, the present embodiments areto be considered as illustrative and not restrictive, and the inventionis not to be limited to the details given herein, but may be modifiedwithin the scope and equivalents of the appended claims.

1. A method for spinning a wafer to enable rinsing and drying, themethod comprising: engaging the wafer at a wafer processing plane;spinning the wafer; moving a wafer backside plate from a first positionto a second position as the spinning of the wafer proceeds to an optimumspinning speed, the second position defining a reduced gap between anunder surface of the wafer and a top surface of the wafer backsideplate; and repositioning the wafer backside plate from the secondposition to the first position as the spinning reduces in speed, thesecond position defining an enlarged gap to enable loading and unloadingof the wafer from the engaged position.
 2. The method of claim 1,wherein the operation of engaging the wafer at the wafer processingplane is performed by holders.
 3. The method of claim 1, wherein thebackside plate includes a central cylindrical edge lip having an innersurface that defines a central aperture.
 4. The method of claim 3,further comprising: providing a pin on the inner surface of thecylindrical edge lip; providing a height adjustment slot on a shaftconfigured to fit within the central aperture; and inserting the pininside the height adjustment slot such that the pin slides from a firstpoint in the height adjustment slot to a second point in the heightadjustment slot during rotational wafer processing.
 5. The method ofclaim 3, further comprising: providing a pin on a shaft configured tofit within the central aperture; providing a height adjustment slot onthe inner surface of the cylindrical edge lip; and inserting the pininside the height adjustment slot such that the pin slides from a firstpoint in the height adjustment slot to a second point in the heightadjustment slot during rotational wafer processing.
 6. A method forspinning a wafer to enable rinsing and drying, the method comprising:engaging the wafer at a wafer processing plane; spinning the wafer and abackside plate, the backside plate being defined below the waferprocessing plane; moving the wafer backside plate from a first positionto a second position as the spinning of the wafer proceeds to an optimumspinning speed, the second position defining a reduced gap between anunder surface of the wafer and a top surface of the wafer backsideplate; and repositioning the wafer backside plate from the secondposition to the first position as the spinning reduces in speed, thefirst position defining an enlarged gap to enable loading and unloadingof the wafer from the engaged position.
 7. The method of claim 6,wherein the backside plate is configured to include a cylindrical edgelip having an inner surface that defines a central aperture.
 8. Themethod of claim 7, further comprising: providing a pin on the innersurface of the cylindrical edge lip; providing a height adjustment sloton a shaft configured to fit within the central aperture; and insertingthe pin inside the height adjustment slot such that the pin slides froma first point in the height adjustment slot to a second point in theheight adjustment slot during rotational wafer processing.
 9. The methodof claim 6, wherein the operation of engaging the wafer at the waferprocessing plane is performed by holders.
 10. A method for spinning awafer to enable rinsing and drying, the method comprising: providing awafer over a process bowl; engaging the wafer at a wafer processingplane; spinning the wafer and a backside plate, the backside plate beingdefined below the wafer processing plane; raising the wafer backsideplate from a lower position to an upper position as the spinning of thewafer proceeds to a process spinning speed, the upper position defininga reduced gap between an under surface of the wafer and a top surface ofthe wafer backside plate; and lowering the wafer backside plate from theupper position to the lower position as the spinning reduces in speed,the lower position defining an enlarged gap to enable loading andunloading of the wafer from the engaged position.
 11. The method ofclaim 10, wherein the operation of engaging the wafer at the waferprocessing plane is performed by holders.
 12. The method of claim 10,wherein the backside plate includes a central cylindrical edge liphaving an inner surface that defines a central aperture.
 13. The methodof claim 12, further comprising: providing a pin on the inner surface ofthe cylindrical edge lip; providing a height adjustment slot on a shaftconfigured to fit within the central aperture; and inserting the pininside the height adjustment slot such that the pin slides from a lowerpoint in the height adjustment slot to an upper point in the heightadjustment slot during rotational wafer processing.
 14. The method ofclaim 12, further comprising: providing a pin on a shaft configured tofit within the central aperture; providing a height adjustment slot onthe inner surface of the cylindrical edge lip; and inserting the pininside the height adjustment slot such that the pin slides from a lowerpoint in the height adjustment slot to an upper point in the heightadjustment slot during rotational wafer processing.
 15. A method forspinning a wafer to enable rinsing and drying, the method comprising:(a) providing a wafer over a process bowl; (b) engaging the wafer at awafer processing plane; (c) spinning the wafer and a backside plate, thebackside plate being defined below the wafer processing plane; (d)raising the wafer backside plate from a lower position to an upperposition as the spinning of the wafer proceeds to a process spinningspeed, the upper position defining a reduced gap between an undersurface of the wafer and a top surface of the wafer backside plate, thereduced gap configured to reduce turbulent airflow under the wafer; (e)lowering the wafer backside plate from the upper position to the lowerposition as the spinning reduces in speed, the lower position definingan enlarged gap to enable loading and unloading of the wafer from theengaged position; (f) disengaging the wafer; (g) removing the wafer fromover the process bowl; and (h) repeating (a)-(g) for additional wafers.16. The method of claim 15, wherein the operation of providing the waferover the process bowl is performed by an end effector.